I am looking to pick up a camera. Can you share your experience with the models you have used? As far as I know, there are the helmet mounted, head strapped and handle bar mounted types. Advantages/disadvantages? Ease of installation?

Waterproof-ness is a definite plus. If I can use it for other purposes like skiing, that would be great.

I've been through several cameras, including the Contour Roam, the Sony ActionCam, and the GoPro Hero3 White. I now use a pair of RD32II cams, $125 each on eBay (mostly shipped from China, expect a 2 week delivery time).
Mounting:

I've been through several iterations of mounting on the bike, but it's just too much vibration and it destroys the image quality. The RD32II is VERY light and two of them is not that much weight.

I use a Drift Ghost HD mounted on the fork, handlebars, chainstay, and helmet. I'm big on getting different angles and editing them together later. Makes for a more interesting video. Key advantages to this camera were the fact the lens can be rotated to always be in the correct orientation, wireless remote, 'loop' video recording (where it's always recording and you just press a button to capture 2 minutes of video when something cool happens), and the built in screen.

Used it on Ragbrai this year and was extremely happy with the performance and video quality.

I had the GoPro Black but was not a fan of it. Battery life was horrible and it kept locking up.

Bar mounted Contour ROAM2 in front (bought before they went out of business )

Rack mounted Monoprice MHD Actioncam in rear.

My Roam arrived the day they went under. Still haven't used it since the SD card I had out of my Vivita rDVR785HD-(POS) was not compatible. I saw postings in many other forums (Motorbike, skiing, surfing etc) where people were talking about scrambling to get the remaining stock. Why? It's electronics. If the parent goes out of business, they do not become collectible, they become disposable. Perhaps I should repack mine and put it on EBay before everyone gets that clue.

I saw postings in many other forums (Motorbike, skiing, surfing etc) where people were talking about scrambling to get the remaining stock. Why? It's electronics. If the parent goes out of business, they do not become collectible, they become disposable.

I think most people try and snatch up accessories and possibly additional units for spare parts like the battery. A $200-$300 camera is certainly not a disposable item to most people, myself included especially if you already have more than one.

cyclists should have license plate readers so we know the background of the drivers that harass us. it would also be good to know if they have a license to carry for example ... I mean you don't want to mess with those dudes

Been there, Detroit, NYC, Syracuse, Honolulu. I've been hit three times and a front facing camera wouldn't have caught any. I've been broad sided twice and hit from behind once.

That's why I ride with two. The lens angle on modern cameras is good enough to pick up cars approaching from the side. You don't necessarily have to show the vehicle approaching for evidence though - just the front facing camera will almost always show that you were obeying all the laws, were in the proper place and lane, were not running a red light, etc, up to the moment of impact, which will almost always put the truth to the motorist's usual bag of lies (He was all over the road, he veered in front of me, blah, blah blah).

I figure I'll be able to provide evidence for incidents that I'm near but not involved with too - I've witnessed several before I got the cameras and having a video record would have been helpful (especially in the hit-and-run that I witnessed, where I was more worried about helping the pedestrian than reading the plate number).

I saw postings in many other forums (Motorbike, skiing, surfing etc) where people were talking about scrambling to get the remaining stock. Why?

I'm not really sure, especially since, in my experience, it's not actually an unusually good camera. The $125 Chinese camera that I have now is actually nicer and has better image quality than the Roam that I used to have (in fact it's a better camera than the Sony and at least on par with the GoPro white as well)

I use a super cheap "Action Shot" from Jakks Pacific, mounted on the bars. If I had the cash, I'd probably go with a GoPro Hero; the image quality I've seen from Go Pro is worlds ahead of what I see from most other similar cams.

I'm finding that the RD32II image quality is better than the cameras I've had before including the Contour Roam, the Sony ActionCam and the GoPro Hero3 White.

The other GoPros, Silver or definitely the black, would probably be better, but in the $200 and below range the RD32II works for me. I can get readable license plate numbers from passing cars with more reliability with it than the others. RD32II is about $125 shipped.

I've had the Hero, Hero2 and now the Hero3 Silver. I've had no trouble with any of them except one of my Hero3's. I couldn't get it to turn on without removing and re-installing the battery. Replaced under warranty but now the new one won't go on at all. I use the handlebar mount on the front and a small pvc pipe screwed into a pvc "t" with 2 backets bolted to the seat rails for the rear.